Income Taxes - Narrative (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2019	Dec. 31, 2018	Sep. 30, 2018	Dec. 31, 2017
Corporate federal income tax	21.00%	21.00%	24.30%	35.00%
Deferred tax asset, income tax expense (benefit)	$ 600
Deemed repatriation tax	800
Undistributed Earnings of Foreign Subsidiaries	11,000		$ 12,700
U.S.
Valuation Allowance, Deferred Tax Asset, Change in Amount	241
Operating Loss Carryforwards	2,000		1,000
State
Valuation Allowance, Deferred Tax Asset, Change in Amount	241
Operating Loss Carryforwards	4,800		$ 2,000
Tax Credit Carryforwards	55
U.K.
Operating Loss Carryforwards	$ 8,200